Improve auth framework with authenticator type.

[Thisara-Welmilla]

Task issue:

• Custom authenticator adapter for user authentication with external service  product-is#20887

With above feature, we will introduce an authentication adapter that extends the AbstractApplicationAuthenticator and implements the FederatedApplicationAuthenticator class. This adapter will support to authenticated both LOCAL and FEDERATED users and user type will be defined at runtime. The authentication flow will need to accommodate both types. To achieve this, the following improvements will introduced with this PR:

1. Introduced new authenticator types (LOCAL, FEDERATED, REQUEST_PATH, FLOW_HANDLER, CUSTOM, UNDEFINED).
2. Introduce new method, getAuthenticatorType() to the ApplicationAuthenticator interface, with UNDEFINED as the default return value.
3. The authenticator interfaces that extend ApplicationAuthenticator will override the getAuthenticatorType() method to return their specific authenticator type.
4. The some authentication flows logic differs based on the instanceof FederatedApplicationAuthenticator check, which ideally should be based on the authenticated user (isFedUser()) of the corresponding step. Those will be replaced with AuthenticatorType.FEDERATED.equals(authenticator.getAuthenticatorType()) to support the existing behavior.
5. To handle user type for the custom authentication adapter at above(4) places, the following check will be added: (AuthenticatorType.CUSTOM.equals(authenticator.getAuthenticatorType()) && stepConfig.getAuthenticatedUser().isFederatedUser()).

[malithie]

Is this needed ?
Does this authenticator get returned back in authenticator API ?

[Thisara-Welmilla]

No this authenticator get returned back in authenticator API. But as we are overriding this method in all other marker interface, though of adding for this also.

If this is unnecessary will remove this.

[malithie]

Don't we need to check for the user here ?

[Thisara-Welmilla]

At this point, the authentication have not happened yet, therefore, cannot check user type. Also this check is just to decide, what should be goes to diagnostic log; whether LOCAL and specific idp name based on the authenticator Type (as local authenticators does not have associated IDP).